CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	0	0	0
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000	300,000,000
Common stock, shares issued	37,068,904	37,068,904	37,068,904
Treasury stock, shares	13,698,990	13,744,395	13,744,474